LED signals, such as LED traffic signals, present numerous advantages over incandescent lamp traffic signals. The use of LEDs provides a power consumption savings and extremely long life compared to incandescent light sources. The long life span of the LED signals leads to improved reliability and lower maintenance costs.
Due to the large number of existing incandescent traffic signals, most LED signals are designed for incandescent lamps. In order to meet existing signal standards and/or allow retrofitting into signals originally manufactured for use with incandescent light sources, LED signals mimic the front housing diameter and depth restrictions of the prior incandescent signals. To allow for an easy retrofit without requiring significant changes to the preexisting AC power distribution and logic circuits, LED signal assemblies typically incorporate a power supply to drive the LEDs at a lower, controlled, direct current power level.
LED signal lamps generally include a housing designed to be retrofit into existing incandescent traffic light signals, and is closed with a cover. Since the LED signal lamps are implemented substantially outside subject to nature's elements, it is important that the lamp is impervious to water. Typically, signal lamps are designed such that a watertight seal is created between the housing and cover with the use of an o-ring or gasket, such as is described in U.S. Pat. No. 7,237,924, the disclosure of which is fully incorporated herein. The o-ring provides a dust and water-resistant seal and is preferably made of EPDM material. However, the use of an o-ring or gasket creates the need for additional parts and therefore increases cost of production. It is therefore desirable to create an LED signal lamp capable of forming a watertight seal between the housing and cover without the use of an o-ring or gasket, thereby reducing costs and part count, while improving ease of assembly.